Means for supporting the electrodes of thermionic devices



June 28, 1932. H. J. ROUND E'rAl.

MEANS FOR SUPPORTING THE ELECTRODES OF THERKIONIC DEVICES Filed Feb. 25. 1922 Patented June 28, 1932 UNITED STATES PATENT OFFICE HENRY JOSEPH ROUND, OF LONDON, AND WILLIAM JAMES FICKEN, OF SOUTHEN-D-ON- SEA, ENGLAND, ASSIGNORS TO RADIO CORPORATION OF AMERICA, A CORPORATION OF DELAWARE MEANS non SUPPORTING THE nnncrnonns or rnnniuromc DEVICES Application filed February 23, 1922, Serial No. 538,512, and in Great Britain March 21, 1921.

In thermionic devices it is desirable that the electrodes should be Supported as securely as possible and at the same time it is necessary that they should be effectively insulated rom one another.

The object of this invention is to provide improved means for supporting and insulating the electrodes.

According to this invention an electrode of a thermionic device is supported and insulated by means of a support made of quartz. Preferably the quartz support consists of a stem surrounded for a considerable portion of its length by acylindrical part which is preferably also constructed of quartz. On to each end of the stem may lit supports or connections of metal.

It frequently happens that several electrodes are supported on various parts of the glass of which the containing vessel is con structed, the glass in between the points on which the electrodes are supported being used to insulate the electrodes from one another. It has been found that the insulation of the glass between the various electrodes becomes insuficient owing either to the tem perature to which the glass is raised or t0 a metallic deposit upon the inside of the glass or to both circumstances. In order to obviate this diliculty according to the invention a sheet or sheets of mica is or are interposed between the electrode and the glass on which it is supported. In some cases it may be sufiicient to employ a single sheet or layer of mica, but it is preferable to employ two adjacent layers having between them a space of considerable length compared to its width, so that no metallic deposit can be formed upon the inner surfaces of the mica.

Our invention as illustrated by the drawing in which Figure 1 is a section through a quartz support. Fig. 2 shows a valve in accordance with the invention. Fig. 3 shows a fragmentary view of a thermionic device having a layer of mica around the stem. Fig. l Vis a modification of Fig. 3. While Fig. 5 shows an enlarged sectional view of the thermionic tube shown in Fig. 2. The support Shown in Fig. 1 consists of a solid central stem A surrounded by a cylindrical part B.

Figure 2 shows a valve comprising a closure member l in which the filament 2 and grid 3 are supported on areentrant glass stem .4 at one end of the member l in a known manner` and the cylindrical anode C is supported at 5 on `a reentrant stem 6 at the otherl end of the .closure l also in a known manner. In order to retain the anode C correctly spaced in position with respect to the grid 3 the upper end of the anode is provided with supports D (usually three) attached to arms E carried by a supporting frame or ring G. The ring G is in turn carried by the supports F for the grid. Quartz insulators B of Figure l serve as the connections between the corresponding parts D and E. The ends ofrD and E are usually made hollow and lit tightly over the stems A ofthe quartz supports as shown in Figure 5.V

Figure 3 shows part of a valve in which an electrode VH is supported from a glass stem I with the interposition of a piece of mica J. Figure A is a similar view showing two cylindrical Vpieces'of mica J and K;the piece J is considerably shorter than the piece K so that spaces L are formed .at each end between the outer piece K' and the glass.

Having described our invention what we claim isi` 1. A thermionic device comprising an evacuated envelope having a reentrant portion, a plurality of electrode supports mount ed thereon, and an electrode carried by said supports, each of said supports comprising terminal segmental metallic sections and an intermediate independent segmental section of insulating material.

2. A thermionic device comprising an evacuated envelope having a reentrant portion, a metallic electrode support mounted on said reentrant portion, an electrode supported therefrom, a second electrode also supported from said metallic support comprising a supplemental supporting member having terminal metallic portions and an intermediate portion of insulating material.

3. A thermionic device comprising an evacuated enclosure, a support therein, an electrode carried by said support, and an insulator of different material forming a portion of the support, said insulator comprising a stem and a surroundin cylinder integral at its `lower end with said stem and spaced therefrom, said stem being arranged to form a connection for receiving another portionof the electrode support.

4. In a thermionic device, a glass enclosure having a reentrant portion, an electrode in said enclosure, a support mounted on said reentrant portion, a second electrode carried by said support, and insulators connecting separate parts of said support, said insulators each comprising a stem and a sleeve surrounding said stem integral therewith at its lower end and spaced therefrom to prevent leakage between said electrodes.

5. A thermionic device comprising an eX- hausted envelope having oppositely disposed reentrant portions, electrode supporting means mounted upon and extending beyond each reentrant portion, an electrode carried by the extended portion of each of said supporting means, and a member interconnected between the extended portion of one of the electrode supporting means of one of said electrodes and the other electrode for maintaining said electrodes in liXed spaced relation.

6. A thermionic device comprising an eX liausted envelope having oppositely disposed reentrant portions, electrode supporting means mounted on each reentrant portion, a grid electrode carried by one of said supporting means, a plate electrode concentrically arranged about said grid electrode and carried by said other supporting means, and a member comprising terminalmetallic portions and an intermediate insulating portion supporting means and the plate electrode, supporting means and the plate electrode whereby said electrodes are effectively insulated from one another and in fixed spaced relation.

HENRY JOSEPH ROUND. WILLIAM JAMES FICKEN.

CERTIFICATE 0F CORRECTIN.

Patent No. 1,865,142. June 28, 1932.

HENRY JOSEPH ROUND ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as foiiows: Page 2, iine 39, claim 6, strike out the Words "supporting means and the plate" and insert instead interconnected between the grid; and that the said Letters Patent should be read with this correction therein that the same may eonform to the record of the case in the Patent Office.

Signed and sealed this 1st day of November, A. D. 1932.

. M; E. Meere, (Seal) Acting Cemmissener of Patents. 

